In all US states, you must be at least 21 years old in order to purchase alcohol. It is also a criminal offense in all 50 states to make false statements (including fabricating IDs) in order to purchase alcohol. However, states can vary whether possession and consumption are also illegal in all circumstances. In some states you may also be charged with “Internal Possession,” which refers to alcohol inside your body. You may be charged with this as a result of a blood, urine, or breath test or, in some states, for merely “showing signs of intoxication,” even if you are found with no alcohol and you were not seen consuming it.
The drinking age also has the effect of allowing establishments to discriminate and refuse you entry to an establishment because of your age, even if you do not drink. There are also laws that prevent you from having certain jobs that involve the serving or selling of alcohol or that punish people for having young people drink on their property. Additionally, in each state the acceptable Blood Alcohol Content (BAC) limit for older people is 0.08, but young people are subject to much stricter BAC laws, allowing for very little margin of error.